The development of advanced electronic devices that demand improved signal transmission has increased the need for custom installations of high definition multimedia interface (HDMI) audio video connections in the field. One major problem is the difficulty of adding (i.e. terminating) a male connector (i.e. plug) onto a standard HDMI cable in the field. Many installers prefer or are required to run the raw HDMI cables and terminate the HDMI plugs in the field instead of using the factory pre-terminated HDMI cables for many reasons including: a) In many buildings the cables are required to be run inside conduit to meet safety codes, however the HDMI plug of a factory made cable is too big to be pulled thru the conduit and the only workable solution is to pull the raw HDMI cable through the conduit and then to put on the HDMI plug afterwards in the field; b) Most electronic devices are mounted in standard racks where the wires connecting the devices in the rack are dressed neatly and cut to the proper length. Since the factory pre-terminated cables only come in several fixed lengths, the extra cable would have to be coiled up in the rack resulting in poor electrical performance and appearance. It is desirable to run raw HDMI cable which is cut to the proper length depending on the installation and then to put on the plugs on in the field; c) In many buildings the HDMI cables are installed and sealed inside the walls. If one plug is damaged then the wall has to be knocked open to replace the entire HDMI cable. There is a demand for the HDMI field termination system for the installers to cut off the damaged plug and put on a new one in the field; d) Safety codes typically require the cables running above tiled fake ceilings in classrooms and conference rooms to meet the plenum UL requirements. The plenum HDMI cables are only available in the form of raw cables as of now. These cables need to be terminated in the field with HDMI plugs.
Though solder free field termination connectors have been commercialized none has been successful for filed termination since they include short comings that affect durability and signal quality of the connectors. For example, no current solderless connector components are sufficiently interlocking for field termination applications resulting in reversibility of the components and loosening of the connection over time. In some cases factory machine heat sealing is employed to secure connector components together and within shells which is impractical in the field.
Further some of these connectors have thin plastic walls in the internal wire holders which crack under typical field pressure or temperature changes resulting in loosening or complete loss of connection over time. To date there are no overall metal shells which results in poor signal grounding and shielding. Also lack of an overall metal shells results in the front probe of the HDMI connector being easily snapped off the HDMI connector body under normal use.
One problem that has escaped workable a solution is that HDMI male connectors are somewhat loose when mated to their female receptacles and often are disconnected inadvertently causing field calls to correct disconnects from angry customers. Generally, HDMI cables are relatively thick and stiff applying constant torque and tension that can pull a connector plug loose from the mated female connector. In most cases it only takes about 3 lbs of pulling force to remove a HDMI cable connected to an electronic device. These problems are made worse by tight spaces common in installations like the space between the flat panel HDTV and the wall, coupled to tilting and panning features on flat panel HDTV wall mounts.
In professional settings there exists a desire and need to have every HDMI cable connection locked to avoid problems from loose and disconnected connectors at critical presentations and meetings. Though the HDMI specifications include square holes present on the bottom of the male probe that connect with friction springs in the female receptacle shell these are inadequate. The HDMI specifications optional friction hole and spring combination is designed primarily for the grounding of connections and fails to correct the common disconnect problems since they do not generate sufficient restraining force to adequately keep the male connector in place. Attempts to fix this problem include adding a thumb screw that requires the female connectors to have the compatible screw threads or active release button lock that requires one to squeeze the male connector body to open a lock tab; however these are cumbersome and have not been adopted due to their short comings. What is needed is a seamless universal male connector that is backwards compatible with existing female HDMI connectors in use and that has increased retention force that essentially locks the connector in place. Connectors that do not add such non-standard active means but are easily and simply disconnected when needed are in demand.
The increased number for custom installations has created needs for better cables that speed installations while at the same time maintain and also improving signal quality. Installers need to rout and dress the wires in cables for equipment racks requiring cutting the wires neatly to proper lengths before terminating the connectors. Current methods for termination of soldering or crimping 19-pins for Type A HDMI cable connectors are difficult to accomplish in the field but are also is labor intensive resulting in reduced productivity and reliability. Though various flat cables are commercially available most of these suffer draw backs. For example flat cables pose problems for pulling through conduit and often hang up due to their flat configuration. On the other hand the HDMI cable factories also face the need to increase the productivities for cable termination while the current methods involve separating 19 wires, preparing them one by one for soldering or crimping and thus these methods are labor intensive and low in productivity. Thus, improved cable designs are needed to address these problems both in the field and in production of cables with connectors in the factory.